Power-operated hook dog



Nov. 8, 192?.

, H. PERCY POWER OERTED HOOK 'DOG Filed Qrl 22, 19231 A TTORNE YS.

Patented Nov. 8, 1927.

. lamaca) PATENT OFFICE.

`EDWIN II. PERCY, OF FORT BRAGG, CALIFORNIA,y AssI'GNoR To BERCYELECTRIC nos, INC., or A:PORT BRAGG", CALIFORNIA, A CORPORATION orCALIFORNIA.

POWER-OPERATIID HOOK DOG.-

" Application area April 22, 192e.v serial No. 103,740.

This invention relates to power-operated hook 4dogs for saw-millcarriages.

In my prior application, Serial Number 684,104, filed January 3, 1924:,I show a hookr dog hingedly mounted on an arm, which arm is rigidlyconnected to a spur gear.

The extent of the hinged movement 1s limited in both directions by stopsyor lugs which contact with the rim of the gear. .Powerv means, such asa reversible motor, drives the gear, and thereby the hook dog 1s raisedkand lowered, the hinged connection serving to impart an inward pull tothe .dog after it strikes the log, so as to pull thelatter against theknee. y

The present invention has for its object to simplify and improvetheconstruction and operation of a hook dog. of this general type, onefeature of special importance being the provision of novel eccentricmeans between the driving gearand the dog, whereby to prevent the logfrom rolling away from the knee through the tendency ofthe driving gearto turn backwardly under the force of the strains imposed thereon.Further novel features are the provision of a frictional mounting forthe driving gear, so that it may continue to rotate after the dog isimbedded in the log; also the use of worm gearing which will tend to actas a lock to prevent backing up of the gearsv when the dog is in the logand the power is shut off. Other novel and advantageous features will`become apparent upon a further understanding of the invention, one formof which is illustrated in the accompanying drawing, wherein Fig. 1shows a vertical sectional view of a power-operated hook dog embodyingmy invention 4 Fig. 2 shows a cross-section taken on the line II-II ofFig. l;

Fig. 3 shows a section taken on the line III-III of Fig. 2, illustratingthe dog in position where itmeets the log; o Y

F ig. 4 shows a view similar to F ig.` 3,w1th

o the dog driven home into the log.

Referring in detail tothe accompanying drawing, 10 indicates the headblock of a saw-mill carriage, upon which is slidably mounted a kneeframe 11, carrying a hook dog 12 and its actuating mechanism. The saidhook dog is provided with a hub portion 14 journaled upon a disk 15eccentrically mounted on a shaft 16. At one sid-e the For driving theeccentric there is mounted on the outer end thereof arworm` gear 23,which gear is frictionally held against the said eccentric disc by meansof a plate 24 bolted on to the said eccentric disc and pressed againstthe face of the worm gear by springs 25. A screw 26 on a horizontalshaft meshes with the said wormy gear and this screw shaft is connectedby meansof a universal coupling 27 to a motor 28. The motor as -s'howninthe present instance is a. reversible electric motor, but may be anyother type of power appliance capable of rotating the said shaft ineither direction.

The normal inoperative yposition of the hook dog is that shown in Fig.1, where the Y said. dog is in vertical position, restingagainst astop29, and the lug 20 on the eccentric disc is engaged with theshoulder 21 at the left. The motor, through the gearing, will turn theeccentric disc to the left', and the frictional connection betweentheeccentric disc and the hub .will cause the dog to swing downwardly until,its point strikes the log, as shown in Fig. 3. At this time the dogwill cease swinging and the eccentric will continue to turn, untilVlinally the lug 20 strikes the shoulder at the right of the hub, asindicated in Fig. l.V Thereby Vthe high point on the eccentric will havemoved from a position pointing upwardly to a position pointingdownwardly, thus Vcarrying the point of the dog downwardly and .inwardlytowards the knee. This will insure that; the logis tightly gripped Y andj drawn closely o y against the knee. The lug 2,0, upon'striking.

of the dog, as shown in Fig. li, ,the` high point of the eccentric isSubstantially on a line with the `point of the dog, and the axis of theeccentric, so that any pull applied` tol When it is desired to releasethe dog, the

motor is reversed, whereupon the eccentric turns to the right, thuslifting the point of the dog out of the log. Once `the point is freefrom the log the arm will swing up A ward'ly with the eccentric, untilit strikes the stop 29, whereupon the eccentric will continue to-rotateuntil stopped by contact ofthe lug 2O with the shoulder on theleft sideof the hub. In this position the parts arer restored toliiorinalinoperative position, with the high point of the eccentricpointingupwardly.

"To prevent injury to the mechanism in case `the dog should be operatedby accidenty when" there is no log on the carriage, I provideaspringbuifer 30 near the front of the knee in position to be engaged by4the hub of the dog before thepoint strikes the head block. Y V

`Various changes in the construction `-and arrangement of the severalVparts herein shown and describedn'iay' be einployedhwithvout departinglfreni-"the spirit of my invention, as disclosed in the appendedclaims.`

Having thus described my inventiomwhat I claim as newand desire tosecure by Letters Patent isz l. In a sawemill carriage, a knee, a hookdog, and eccentric means for actuating the dog seas to impart theretofirst a swinging movement towards the log andthen a moves'` ment bodilydownwardly and towards the knee, and a rotatable niotor for driving theeccentric means `in either direction, whereby to engage and disengagethe dogwith a log. 2; In a saw-mill carriage, aiknee`,'ahook dog, saidhook dog having `a hub portion, an, eccentric disc on which the hubportion ismounted,` means for rotating the eccentric disc, andconnections between the-latteriand the hub port-ion, whereby the dog'will be caused to swing towards" thelog until it strikes the same, andthereafter `will be moved bodily downwardlyiand towards-the knee, .and arotatable" motor for driving said eccentric disc in either direction,whereby to engage and disengage `thejdog with` a log.`

\ 3. In a saw-millfcarriage, a knee, a hook dog having a Vhub portion,an eccentric disc` `onwhich said` hub portion is mounted, means forrotating the eccentric disc,alnd frictional and positiveA connectionsbetween the. said eccentric discand hub portion whereby theV higliipointof the eccentric disc-will be ex tended upwardly when the dog-is outf'ofthe log, and when the vvdog is engaged withthe log such high point ofthe eccentric disc will bef disposed on the opposite sideof the axis ofsaid disc and substantially'rin line with the point ofthe dog.

t. In a saw-mill carriage, a knee, a hook dog having a hub portion, aneccentric Vdisc on which the said` hub portioiris mounted', i

frictional members connecting the hub pOr-,

tion 'Lwithv the disc, and Pspaced members forming `positive stopsbetween the disc and hub, wl'iereby when the 'dogstrikes a log theeccentric disc may turn relatively a limited distance to pull thedogdownwardly and towards the knee, and lmayA also turn `relativelyAinlthe lopposite` direction to disengage the point of the dog frenithelog beroretne stop becomes eli'ective.` Y

5. In asaw-inill carriage,`a knee, a hook i dog, means .for actuatinglthe dog-so as to impart thereto iirst a swinging movement towards tne.log and then `a bodi yA movement downwardly" and" towards the knee, anda gear "frictionally connectedto said actuating means for operating thelatter, andpow'er-` operated `means ,for driving the said gear,

whereby whenthe dog isuiinally stopped by its 'engagement with theflogsaid frictional connections will permit the power-operated mechanism tocontinue to move;

G. In asaw-mill carriage, a knee, `a hook dog, ineansfor actuating thehook dog so as to swing `the same towards the log-and then to l draw .itinwardly `towards the knee, worin gear for driving said actuatingVmeans, 'a screw `engaging the worm gear, `and al reversible motor foroperating the screw. i

7. In a saw-mill carriage, a knee frame," a shaft jonrnaled thereon,` aneccentric disc fixed to said shaft, a hook dog carriedib'y the eccentricdisc, a` gear frictionally :connectedwith the eccentric disc, andpoweroperated means for driving said gea-rf in E" either direction. Y

Y i PERCY.

